Device for determining a physical value of a liquid flowing in a pipe

ABSTRACT

A device for determining a physical value of a liquid flowing in a pipe, without contact with the liquid. The device includes: a sensor for the physical value; a connector to insert into the pipe and including: an internal passage extending between two apertures, a flexible membrane for a pressure sensor, forming a wall of the internal passage; and a fastening mechanism for fastening the sensor onto the connector. The sensor is a temperature sensor fastened to the connector with the sensitive part of the sensor turned towards the membrane.

The invention relates to the determination of a physical value of aliquid flowing in a pipe, without contact with that liquid.

Circuits are known for certain liquids, in particular biologicalliquids, in which the components in contact with the liquids aresingle-use components.

To know the pressure of the liquid flowing in such a circuit, aconnector has already been proposed for insertion in the pipe in whichthe liquid flows, that connector comprising an internal passageextending between two apertures for inlet/outlet; a flexible membraneforming a wall of that internal passage; and fastening means for apressure sensor in order to attach the latter to the connector in aposition in which its sensitive part is in contact with the flexiblemembrane.

Thanks to the flexible character of the membrane, the internal pressureof the connector (pipe pressure) may be transmitted to the pressuresensor.

The pressure sensor can be re-used whereas the connector inserted intothe pipe is, like the pipe, a single use item.

The invention is directed to the provision of a device for determiningthe temperature of a liquid flowing in a pipe comprising, like theaforementioned device, a single use connector.

To that end it provides a device for determining a physical value of aliquid flowing in a pipe, without contact with said liquid, said devicecomprising:

-   -   a sensor for said physical value;    -   a connector to insert into said pipe and comprising:        -   an internal passage extending between two apertures,        -   a flexible membrane for a pressure sensor, forming a wall of            said internal passage; and    -   means for fastening said sensor onto said connector;

characterized in that said sensor is a temperature sensor fastened tosaid connector with the sensitive part of said sensor turned towardssaid membrane.

Thus, the device according to the invention uses, to determine thetemperature, a connector similar to that of the aforementioned device todetermine the pressure of the liquid, this connector comprising inparticular a flexible membrane provided to cooperate with a pressuresensor.

Although it may seem surprising, the flexible membrane for a pressuresensor is also capable of cooperating with a temperature sensor,particularly but not exclusively by implementing the preferred featuresset out below.

The fact of using the same connector to determine the pressure of theliquid flowing in the pipe or to determine the temperature therein makesit possible to take advantage of economies of scale and a simplifiedimplementation for a single-use circuit.

According to preferred features:

-   -   said sensor comprises an infrared temperature probe; and a        sheath enveloping said probe and comprising at one of its        longitudinal ends, a stiff plate provided with an aperture; said        plate being disposed between said membrane and said sensitive        part to stiffen said membrane;    -   said sensor comprises an obturating lid formed from an opaque        film, said lid covering the face of said plate turned towards        said membrane;    -   said device comprises means for positioning said sensor relative        to said connector in order for said lid to be in contact with a        face of said membrane;    -   said positioning means comprise a shoulder adapted to cooperate        in abutment with a collar;    -   said lid has constant emissivity in the temperature range from 4        to 40 degrees Celsius;    -   said sheath comprises a cup and a cap assembled together by        screwing;    -   said cap comprises a breech of which the back is formed by said        stiff plate;    -   said probe comprises a head accommodating a converging lens;    -   said fastening means comprise a tapping adapted to cooperate        with a screw thread; and/or    -   said connector is disposable whereas said sensor is re-usable.

The disclosure of the invention will now be continued with the detaileddescription of an embodiment, given below by way of illustrative butnon-limiting example, with reference to the accompanying drawings, inwhich:

FIG. 1 is a cross-section of a device for determining the pressure of aliquid flowing in a pipe, the device being useful for the understandingof the invention;

FIG. 2 is a cross-section of the device according to the invention;

FIG. 3 is an exploded perspective view of the connector of the device ofFIG. 1 and the device according to the invention;

FIG. 4 is a perspective view of the device according to the invention;

FIG. 5 is an exploded perspective view of the temperature sensor of thedevice according to the invention; and

FIG. 6 is a perspective view of the temperature sensor of FIG. 5 in theassembled state;

The device illustrated in FIG. 1 makes it possible to determine thepressure of a liquid flowing in a pipe.

It comprises a disposable connector 2 to insert in a flexible pipe, alsodisposable, as well as a pressure sensor 100 adapted to be partiallyreceived in the connector 2.

The connector 2 will now be described more particularly, with the aid ofFIGS. 1 and 3.

The connector 2 which is of T-shaped profile, is provided to be insertedin series in a disposable flexible pipe. It comprises base 4, an ‘O’ring seal 5, a membrane 6, a stiff ring 7 and a tapped screw 8.

The base 4 is of molded plastics material (here a polypropylenecopolymer that is resistant to gamma radiation). It comprises a straightpipe 10 forming an internal passage 13 extending between two aperturesfor inlet/outlet 11, 12 and enabling the liquid to flow inside theconnector 2. This internal passage 13 is here of constant cross-sectionbetween the apertures 11 and 12.

To enable the insertion and the connection of the connector 2 betweentwo sections of a disposable flexible pipe, two nipples 14, 15 aredisposed at the apertures 11, 12 of the pipe 10.

The base 4 also comprises a bowl 16 which is disposed at the centralpart of the pipe 10.

The lateral wall 17 of the bowl 16 has an octagonal outer cross-sectionwhereas its inner side forms a blind tapping 18 (FIG. 3) provided tocooperate with the screw 8.

The bottom 19 of that bowl 16 (FIGS. 1 and 3) comprises a cylindricalcentral bore 20 which issues into the internal passage 13. This bore 20has a relatively large cross-section by virtue of which the liquidpresent in that bore 20 is continuously renewed (the liquid is nottrapped in the bore 20).

On entering the bore 20 and over the whole of its periphery, the bottom19 also comprises an annular recess 21 having an L-shaped cross-section.

This recess 21 thus forms a groove 21 a adapted to accommodate the ‘O’ring seal 5 and a bore 21 b provided for the reception of the membrane 6and of the stiff ring 7.

The seal 5 is an ‘O’ ring formed from an elastically deformable material(here silicone).

The membrane 6 is formed from a flexible film of single layer ormultilayer plastics material (here linear low density polyethylene(LLDPE)).

The screw 8 is of molded plastics material (here a polypropylenecopolymer that is resistant to gamma radiation). At its opposite end toits hexagonal head 25, it comprises a central cylindrical bore 26, ofthe same diameter as that of the bore 20.

Extending onwards from that bore 26, the screw 8 comprises a tapping 27(FIGS. 1 and 3) of greater diameter which issues at its head 25.

The screw 8 also comprises an annular shoulder 28 situated at thejunction between the bore 26 and the tapping 27.

The mounting of the connector 2 will now be described.

The first step consists of placing the ‘O’ ring seal 5, the membrane 6and the stiff ring 7 in the base 4.

For this, the ‘O’ ring seal 5 is first of all inserted into the annulargroove 21 a. Next the membrane 6 is positioned such that it fully coversthe entry of the bore 20 and the ‘O’ ring seal 5 (FIG. 1). Lastly, thestiff ring 7 is placed above the membrane 6.

The second step consists of screwing the screw 8 into the blind tapping18 of the base 4 to fasten the membrane 6.

The screw 8 thus advances in the tapping 18 until its free end 30 comesinto contact with the stiff ring 7.

The continuation of the screwing then leads to the compression of the‘O’ ring seal 5, the stiff ring 7 making it possible to avoid the freeend 30 of the screw 8 coming to rub directly against the membrane 6which would risk deteriorating it.

Once the screw 8 has been tightened, the membrane 6 forms a wall of theinternal passage 13.

The face 31 of this membrane 6 is thus in direct contact with the liquidflowing in the internal passage 13 while its opposite face 32 isisolated from that same internal passage 13.

The mounting of the connector 2 is thus terminated (FIG. 1), themembrane 6 being situated in register with the bore 26 and the tapping27 of the screw 8.

The pressure sensor 100 will now be described.

This comprises a pressure probe 101, a generally cylindrical sleeve 102enveloping the probe 101 and a hollow screw 103.

The pressure probe 101 comprises a cylindrical metal body 104, anannular collar 105 projecting at the periphery of the body 104 as wellas a membrane 106 situated at one of the longitudinal ends of the body104.

The body 104 houses a processing device which converts the movements ofthe membrane 106 into a signal representing the pressure.

At the opposite end to the membrane 106, the pressure probe 101 alsocomprises a flexible cable 107 to enable it to be supplied with powerand ensure the transmission of the signals sent by the processingdevice.

The sleeve 102 is formed from a barrel 102 a and a tube 102 b screwedtogether and cooperating with the collar 105 to prevent translationalmovement of the probe 101 relative to the sleeve 102.

At the zone of screwing with the tube 102 b the barrel 102 a comprises aprojecting collar 108 adapted to abut the shoulder 28 of the connector 2to position the membrane 106 of the pressure probe 101 against themembrane 6.

The screw 103 comprises a through bore 109 of which the diameter is veryslightly greater than the outer diameter of the tube 102 b such that thescrew is adapted to slide along that tube 102 b.

On its outer face and at its opposite end to its circular head 110, thescrew 103 has a screw thread 111 provided to cooperate with the tapping27 of the connector 2, so as to provide the fastening of the pressuresensor 100 onto the connector 2.

The putting in place of the pressure sensor 100 in the connector 2 iscarried out simply by disposing it such that its membrane 106 faces themembrane 6, and by inserting it into the tapping 27 and the bore 26 ofthe connector 2.

The movement continues until the collar 108 comes into abutment with theshoulder 28, the membrane 106 then resting against the face 32 of themembrane 6.

It then only remains to screw the screw 103 into the tapping 27 in orderto provide the fastening of the sensor 100 in the connector 2.

The position in FIG. 1 (assembled device) is thus attained.

To operate the pressure determining device, the probe 101 of the sensor100 is powered via the cable 107.

The liquid under pressure flowing in the connector 2 leads to thedeformation of the membrane 6, the consequence of which is also toinduce the deformation of the membrane 106 of the pressure sensor 100.

This deformation of the membrane 106 is converted by the probe 101 intoa signal representing the pressure of the liquid flowing in the internalpassage of the connector 2.

The device 1 according to the invention and which is illustrated in theassembled state in FIGS. 2 and 4, makes it possible to determine,without contact, the temperature of a liquid flowing in a pipe.

It comprises a connector 2 as described earlier, but coupled here to are-usable temperature sensor 3.

The sensor 3 will now be described with the aid of FIGS. 5 and 6.

The sensor 3 comprises a temperature probe 40, a sheath 41 envelopingsaid probe 40, an obturating lid 42 and a hollow screw 43 with a roundflat head.

The temperature probe 40 comprises a generally cylindrical body 45 ontowhich is screwed a head 46 in the form of a hexagonal nut.

The body 45 and the head 46 of this probe 40 are hollow and each have anouter wall here of stainless steel.

The head 46 accommodates a converging lens enabling a detection cone tobe defined of which the point (corresponding to the focal point of thatlens) is situated on the lid 42 when the sensor 3 is assembled.

The body 45 houses a detector sensitive to infrared radiation as well asa processing device which converts the radiation captured by the sensorinto a signal representing the temperature.

At the opposite end to the head 46, the probe 40 also comprises aflexible cable 47 to enable it to be supplied with power and ensure thetransmission of the signals sent by the processing device.

The sheath 41 enveloping the probe comprises a cup 41 a adapted tocooperate by screwing with a cap 41 b

The cup 41 a comprises a cylindrical main wall 49 and a bottom wall 50.

The bottom wall 50 has a circular opening 51 provided for the passage ofthe cable 47 of the probe 40.

The cylindrical wall 49 has a screw thread 52 disposed on its outer faceand at its opposite end to the bottom wall 50.

The cap 41 b comprises a breech 55 surmounted by a tapped collar 56provided to cooperate with the screw thread 52.

The back of the breech 55 forms a stiff plate 58 at the center of whicha circular aperture 57 (FIG. 2) is formed to enable the passage of theinfrared radiation towards the sensitive part of the detector of theprobe 40.

The breech 55 furthermore has the same outer diameter as that of thecylindrical wall 49 of the cup 41 a, this outer diameter moreover beingslightly less than that of the central bore 26 of the screw 8 of theconnector 2.

The obturating lid 42 is here formed from an opaque adhesive film (hereof polyimide) of which the emissivity is constant in the temperaturerange from 4 to 40 degrees Celsius.

This lid 42, of the same diameter as the plate 58, is bonded to thelatter so as to completely cover the face of that plate 58 that isoriented towards the membrane 6.

The screw 43 comprises a through bore 60 of which the diameter is veryslightly greater than the outer diameter of the cylindrical wall 49 ofthe cup 41 a such that the screw is adapted to slide along that cup 41a.

The screw 43 has on its outer face and at its opposite end to itscircular head 61, a screw thread 62 provided to cooperate with thetapping 27 of the connector 2.

The assembly of the temperature sensor 3 is made in the followingmanner.

The cup 41 a is first of all engaged in the bore 60 of the screw 43,then the end of the cable 47 is inserted inside that cup 41 a so as tomake it come out by the opening 51.

Next the probe 40 is disposed in the cup 41 a and lastly the cap 41 b isscrewed onto that cup.

Once assembled, the temperature sensor 3 is as illustrated in FIG. 6 andis then adapted to be received partially in the connector 2.

For this, the sensor 3 is disposed such that the lid 42 faces themembrane 6, and sensor 3 is inserted into the tapping 27 and the bore 26of the connector 2.

The movement continues until the collar 56 comes into abutment with theshoulder 28 (FIG. 2), the lid 42 then resting against the face 32 of themembrane 6.

It then only remains to screw the screw 43 into the tapping 27 in orderto provide the fastening of the sensor 3 in the connector 2.

The position of FIG. 2 is thus attained in which the device 1 is in theassembled state in which the sensor 3 is fastened to the connector 2with the sensitive part of the detector of the probe 40 being turnedtowards the membrane 6.

It will be noted that the cooperation of the collar 56 and of theannular shoulder 28 enables reproducible positioning of the lid 42 to beprovided. This avoids any accidental tearing of the membrane 6 whichcould lead to the contamination of the temperature sensor 3 (which isre-usable) by the liquid flowing in the internal passage 13 of theconnector 2.

To operate the device 1, the probe 40 of the sensor 3 is powered via thecable 47. The infrared radiation emitted by the lid 42 after passagethrough the lens 46, enters the sensitive part of the detector.

This radiation is converted by the processing device into a signalrepresenting the temperature which is transmitted via the cable 47.

The presence of a converging lens in the head 46 of the probe 40 enablesthe diameter of the aperture 57 to be limited in order for the lid 42 tohave a maximum area in contact with the plate 58 of the breech 55, whichis stiff.

The lid 42 and the membrane 6 are thus stiffened by that plate 58 whichavoids any risk of bursting of the membrane 6, even in the case of highpressure of the liquid flowing in the internal passage 13 of theconnector 2.

The analysis by the sensor 3 of the emission from that lid 42 enablesthe temperature thereof to be determined with improved precision in thatthe coefficient of emissivity of that lid is constant in the temperaturerange of interest here, i.e. between 4 and 40 degrees Celsius.

Due to the very small thickness of the lid 42, its temperature is thesame as that of the membrane 6 against which that lid 42 is pressed.

In similar manner and on account of the very small thickness of themembrane 6, its temperature is the same as that of the liquid underpressure with which that membrane 6 is in contact.

The sensor 3 thus enables the temperature of the liquid flowing in theinternal passage 13 to be determined, here with a precision of +/−2degrees.

In a variant not represented of the device according to the invention,the sensor does not comprise a lid, the temperature measurement beingmade directly on the membrane or through it.

In another variant not represented, the sensor does not comprise a wall,such as the plate 58, to stiffen the membrane (the pressure of theliquid flowing in the internal passage of the connector being low).

In still other variants not represented:

-   -   there is no cable such as 47 or 117, and instead there is        provided (i) a battery, coupling (magnetic, capacitive, . . . )        means or other powering means and (ii) wireless communication        and memory device such as a RFID chip or Bluetooh or Zigbee        enabled device to communicate remotely with a processor device;    -   the probe does not comprise a lens and/or the aperture in the        sheath has a greater diameter;    -   the temperature ranges are different and/or the emissivity of        the lid varies as a function of the temperature; and/or    -   the sensor comprises a probe other than an infrared probe (for        example a thermocouple in contact with the membrane).

Numerous other variants are possible according to circumstances, and inthis connection it is to be noted that that the invention is not limitedto the example embodiments described and shown.

1. A device for determining a physical value of a liquid flowing in apipe, without contact with said liquid, said device comprising: a sensorfor sensing said physical value; a connector to insert into said pipeand comprising: an internal passage extending between two apertures, aflexible membrane adapted to cooperate with a pressure sensor todetermine the pressure of said flowing liquid, and also adapted tocooperate with a temperature sensor to determine the temperature of saidflowing liquid, said flexible membrane forming a wall of said internalpassage; and means for fastening said sensor onto said connector;wherein said sensor is a temperature sensor fastened to said connectorwith the sensitive part of said sensor turned towards said membrane. 2.A device according to claim 1, wherein said sensor comprises an infraredtemperature probe; and a sheath enveloping said probe and comprising atone of its longitudinal ends, a stiff plate provided with an aperture;said plate being disposed between said membrane and said sensitive partto stiffen said membrane.
 3. A device according to claim 2, wherein saidsensor comprises an obturating lid formed from an opaque film, said lidcovering the face of said plate turned towards said membrane.
 4. Adevice according to claim 3, wherein it comprises means for positioningsaid sensor relative to said connector in order for said lid to be incontact with a face of said membrane.
 5. A device according to claim 4,wherein said positioning means comprise a shoulder adapted to cooperatein abutment with a collar.
 6. A device according to claim 3, whereinsaid lid has constant emissivity in the temperature range from 4 to 40degrees Celsius.
 7. A device according to claim 2, wherein said sheathcomprises a cup and a cap assembled together by screwing.
 8. A deviceaccording to claim 7, wherein said cap comprises a breech of which theback is formed by said stiff plate.
 9. A device according to claim 1,wherein said sensor comprises an infrared temperature probe, and saidprobe comprises a head accommodating a converging lens.
 10. A deviceaccording to claim 1, wherein said fastening means comprise a tappingadapted to cooperate with a screw thread.
 11. A device according toclaim 1, wherein said connector is disposable whereas said sensor isre-usable.
 12. A device according to claim 1, wherein said connector hasa T-shaped profile.